396 FLY OPHRYS. PART n. 



pollen grains penetrate through the stigmas, and fertilize 

 the ovules in the twisted ovary. The double movement 

 of the pollinia, while on the moth's proboscis, is owing 

 to the rapidity with which the viscid matter contracts 

 and dries. Both butterflies and moths frequent this 

 Orchis. Mr. Darwin enumerates twenty-three species 

 of these insects which he had seen with the pollinia of 

 the Orchis pyramidalis attached to their proboscides. 

 Many had two or three pairs ; the proboscis of the 

 Acherontia had seven, and that of the Caradium had 

 no less than eleven of these saddles attached at regular 

 distances from top to bottom of its proboscis. Few of 

 the species of Orchis are visited by bees. 



On account of some resemblance in form, the Ophrese 

 are named after insects. The Fly Ophrys differs in no 

 material respect from the other Orchids. The stem or 

 caudicle of the pollinium, instead of being straight, as 

 in the Orchis mascula, is doubly and almost rectangu- 

 larly bent. The upper membrane of the disc to which 

 the stalk of the pollinium is fixed, being the summit of 

 the rostellum, is exposed to the air, and becomes dry 

 when the flower opens, consequently the disc, though 

 viscid enough on its under-side to stick to an insect's 

 head, is incapable of shrinking, and causing that de- 

 pression of the pollinium, characteristic of all the species 

 of Orchis. The labellum has no spur, but at its base, 

 just below the stigma, there is a deep depression repre- 

 senting the nectary ; and as the pollinia, which cannot 

 be shaken out of their cells, or pouches, are certainly, 

 though rarely, extracted, Mr. Darwin conceives that 

 small insects crawl along the labellum to its base, strike 

 against one of the pouches, extract a pollinium, and fly 

 with it sticking on their head to another blossom, and 

 that while bending their heads into the hollow at the 

 base of the labellum, the pollinium, owing to its doubly 

 bent stalk, strikes the sticky stigmatic surface, and 



